Crystal Lab › Prototype structures › Trigonal
β-CuI (Kurdyumova)
Trigonal · space group P3m1 (No. 156) · Pearson hP12
Symmetry elements and Wyckoff positions (interactive)
β-CuI (Kurdyumova) in P3m1
SettingUnit cell
- Lattice constants
- a = 4.250 Å, b = 4.250 Å, c = 20.860 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 326.3 ų
- Atoms in the conventional cell
- 12 (Cu 6, I 6)
- Formula units Z
- 6
- Pearson symbol
- hP12 — hexagonal / trigonal, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 6 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cu4 | Cu | 1a | 1 | 0.0000 | 1.0000 | 0.4583 |
| Cu5 | Cu | 1a | 1 | 0.0000 | 1.0000 | 0.7917 |
| Cu6 | Cu | 1a | 1 | 0.0000 | 1.0000 | 0.1250 |
| I10 | I | 1a | 1 | 0.0000 | 1.0000 | 0.3333 |
| I11 | I | 1a | 1 | 0.0000 | 1.0000 | 0.6667 |
| I12 | I | 1a | 1 | 0.0000 | 1.0000 | 0.0000 |
| Cu1 | Cu | 1b | 1 | 0.3333 | 0.6667 | 0.3750 |
| Cu2 | Cu | 1b | 1 | 0.3333 | 0.6667 | 0.7083 |
| I7 | I | 1b | 1 | 0.3333 | 0.6667 | 0.5000 |
| I8 | I | 1b | 1 | 0.3333 | 0.6667 | 0.8333 |
| Cu3 | Cu | 1c | 1 | 0.6667 | 0.3333 | 0.0417 |
| I9 | I | 1c | 1 | 0.6667 | 0.3333 | 0.1667 |
The multiplicity and the Wyckoff letter say how many copies of the site the group makes in one cell and on which kind of symmetry element the site sits; the 12 atoms drawn above are these sites multiplied by all 6 operations. Press Wyckoff under Colour to see the sites, and tick a symmetry element on the left to see which atoms lie on it.
How to read the label
AB_hP12_156_3a2bc_3a2bc-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP12, then the space-group number 156, then the Wyckoff letters occupied by each element in turn (Cu: 1a; Cu: 1a; Cu: 1a; I: 1a; I: 1a; I: 1a; Cu: 1b; Cu: 1b; I: 1b; I: 1b; Cu: 1c; I: 1c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: \beta-CuI (Kurdyumova).
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_hP12_156_3a2bc_3a2bc-001 (M. J. Mehl et al., Comput. Mater. Sci. 136, S1 (2017); D. Hicks et al., ibid. 161, S1 (2019) and 199, 110450 (2021); S. Eckert et al., ibid. 240, 112988 (2024)). Symmetry elements, Wyckoff assignment and the diagram are computed on this page from the group operations.
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